Method of preventing malfunction of a magazine type firearm and gage for conducting same



KANEMITSU ITQ Dec. 9. 1969 3,482,322

METHOD OF PREVENTING MALFUNCTION OF A MAGAZINE TYPE (I FIREARM AND GAGE FOR CONDUCTING SAME Filed Nov. 6, 1967 AM G0 I/VVE/VTOR KANE MITSU I70 United States Patent O U.S. Cl. 33-168 1 Claim ABSTRACT OF THE DISCLOSURE A unitary gage capable of dimensionally checking the several dimensions of the magazine of a rapid feed firearm to detect magazine deformation that could cause jamming, excessive feeding or failure to feed cartridges, said dimensional checks thereby making test firing unnecessary.

BACKGROUND OF THE INVENTION Combat military personnel are equipped with an ever increasing variety of equipment to permit each man to successfully meet a wide variety of challenges. To increase mobility and forestall fatigue, the burden to be carried by each individual person must comprise equipment designed to have minimum weight compatible with its function. It is the prevailing practice of riflemen to carry on their person fully loaded magazines of spare cartridges, any of which must be amenable to rapid exchange in a firearm with an exhausted magazine under perilous conditions. Magazine construction utilizing lightweight metal is dictated by these conditions. However, such magazines are more disposed to suffer deformation under the rigors of combat than were their steel predecessors.

SUMMARY OF THE INVENTION It is an object of this invention to teach the aspects of critical magazine dimensions and to teach the construction and use of a gage to measure said dimensions; particularly a compact, durable gage optimized for portability and wear qualities whereby the carriers burden is minimum and reliability and ease of use are optimum.

Heretofore, a rifieman had no way, other than firing a burst of rounds, to ascertain if his weapon would function properly after a magazine received a blow, whether its construction be of steel or of a lighter metal. Combat rifiemen frequently encounter conditions such as scarcity of ammunition supply or an imposed strategic silence which prevent them from checking by the burst of fire method the performance of magazines recently subjected to rough handling; where said rough handling is known to produce deformations that may misfeed ammunition and thereby jam the auto-loading action or prevent ammunition from being fed to the weapon. This condition can have a deleterious effect on the combat effectiveness of units utilizing firearms with light metal magazines. Additionally, the expenditure of great time and effort may be required to restore normal weapon functionability. The invention described herein will permit any rifieman to quietly, economically and efficiently predict a weapons capability of delivering reliable and immediate response to an impending peril after the magazine thereof has been sharply struck.

While an H configuration gage is considered to be optimum and will be described in detail, an alternate L configuration will be shown and briefly described as an example of an alternate configuration for gaging the critical dimensions discussed. Furthermore, it must be expressly understood that the magazines of the type illustrated are See well known in the firearms art and not claimed as part of the invention. Further, it is to be understood that the configuration of the instant invention may be easily modified to accommodate magazines of differing configurations which rely upon a definite magazine recess or projection as part of the means positioning the magazine fixedly with respect to the sliding action of the weapon; or which rely upon lips to restrain the uppermost cartridge against transverse movement while permitting the flying bolt of a sliding action to reach through the lips to engage the uppermost cartridge and urge it axially forward and upward to fill the breech of the weapon. It must be further recognized that the invention taught also pertains to handguns, cannon and other free or mounted firearms, in addition to rifles, which utilize interchangeable magazines to store cartridges for incipient use.

DESCRIPTION OF THE DRAWINGS The following is a detailed description of the present invention made with reference to the attached drawings in which:

FIGURE 1 is a spatial view of a magazine presently used with weapons popularly designated as the M-16 rifle, the AR-l5 rifle and others.

FIGURE 2 is an isometric view of the preferred H configuration magazine gage.

FIGURE 3 is a front view of the gage shown in FIG- URE 2.

FIGURE 4 is a view of a fragment of the gage shown in FIGURE 2.

FIGURE 5 is a spatial view of an alternate L configuration gage.

Referring to FIGURE 1, wherein is shown the outer casing 10 of a magazine containing a spring and spring loaded follower (not shown) which serve to urge cartridges toward bent lips 12 which react through said cartridges to balance the load imposed by said follower. Dimension A, the clear distance between the lips 12, is critical because too close a spacing prevents proper feeding of cartridges while too wide a spacing permits overriding or double feeding of cartridges. Similarly, double feeding or failure to feed result when the lips 12 are bent to some angle other than with respect to the body 10 of the magazine.

A catch notch 14 is integral with and protrudes outwardly of casing 10, its free edge lying in a plane normal to the longitudinal axis of the magazine. Catch notch 14 permits the magazine to be securely locked in a fixed position with respect to the bolt of the weapon using the magazine. Dimension B, the included distance between the free surface of notch 14 and the uppermost surface of each of the lips 12 is critical because too short a distance will cause failure to feed since the bolt will not contact the uppermost cartridge while too long a distance will cause the bolt to strike the lips 12 thereby stopping the bolt or damaging the lips.

Dimension C is a thickness dimension representing the separation between the sidewalls of the magazine. This dimension is critical because too narrow a dimension will cause the follower or cartridges to bind and stop the feed while too wide a dimension will cause a similar result and additionally will prevent loading of the magazine well. Dents or bulges represent local deviations of dimension C with similar result.

Dimension D is the difference or variation detected between the B dimension of each of the lips 12 and is critical because, if significant, it can result in any of the problems related with respect to dimension B.

Dimension E is an angular deviation or variation representing an out of square condition between the end 3 faces 56 and 58 and each of the side faces 52 and 54 of the magazine and is critical because excess-deviation will result in binding of the follower and subsequent failure to feed.

Flatness of the large front and back surfaces 52 and 54 respectively shall be determined by visually examining for bulges or dents which might cause jamming or binding of the cartridges in the magazine.

Referring to FIGURE 2, the preferred embodiment of the instant invention is an H configuration gage having upper arms 20 and 22 joined by a cross member 24. The inboard surfaces 26 and 28 of arms 20 and 22 respectively form parallel planes a fixed distance apart representing the maximum tolerable magazine body dimension C (see FIG. 1), parallel surfaces 26 and 28 in concert with surface 30 of cross arm 24 from cavity 60.

If arms 20 and 22 are caused to straddle the magazine side surfaces 52 and 54 squarely while the magazine edges 56 and 58 are traversed, assurance is had that the magazine body is not too wide. With arms 20 and 22 straddling the magazine, surface 30 of cross member 24, positioned perpendicular to parallel surfaces 26 and 28, is brought into contact with the uppermost part of lips 12, the body dimension B (see FIG. 1) is not too short if surface 32 at the terminus of arm 20 clears the free edge of magazine catch notch 14. With the gage reversed to interchange the position of arms 20 and 22 with respect to the catch notch, dimension B is not too long arms; however, the same failure modes can be anticipated for similar dimensional deviations.

A go to A no go spans a .0360 range.

B go to B no go spans a .0102" range.

C go to C no go spans a .0320" range.

D should not exceed .005.

E should not exceed .005".

Flatness deviations of .010 for dents should not be exceeded.

Flatness deviations of .030" for bulges should not be exceeded.

Referring to FIGURE 4, an L-shaped gage may be viewed as an example of one of an alternate gage which may satisfy the functional aspects of the H configuration taught above, but which lacks the optimization as to compact arrangement which the H configuration provides and which is so desirable in a gage to be carried on the person in the field of combat. The lettered critical dimensions are in exact correspondance with those of the magazine already described.

From the foregoing, it is evident that a compact and convenient field carried gage useful in determining the existence of damage to a magazine may prevent firearm if surface 34 at the end of arm 22 rests on the free su'rr sion position and surface 30 in contact with lips 12 or a lip 12, a visual inspection of dimension D can be made to determine if an excessive difference in height exists between one lip 12 relative to the other lip 12. Similarly, with the upper arms straddling the long edges 56 and 58 of the magazine to measure dimension C, a visual determination of dimension E, is made to insure that the magazine was not excessively out of square.

A no go check on dimension C is readily obtained by attempting to cause the lower arms 62 and 64 of the gage to straddle the long edges of the magazine. These arms will fail to straddle unless the magazine is too narrow since parallel inboard surfaces 40 and 42 are separated by a distance precisely corresponding to the minimum functionable magazine width.

If upper arm 22 is inserted between lips 12 such that parallel inboard surface 28 and outboard surface 36 are parallel to the lips 12, then the A clear dimension between the lips is not too narrow. If inboard surface 28 and parallel surface 38 (outboard of surface 36) fail to pass between lips 12, then the A clear dimension is not too wide.

Suitable gage thickness must be provided to insure that flatness will be maintained and that distortions affecting malfunction and hence be a life saving article among a combatants field gear.

It will be evident that various modifications and variations may be effected without departing from the novel concepts of the present invention.

I claim as my invention:

1. A field gage for a cartridge magazine shell having cartridge positioning lips at an open end and a magazine carried positioning stop spaced from said lips comprising; and H-shaped snap gage having two pairs of upstanding parallel legs joined by a cross member, one pair of upstanding legs having upstanding facing surfaces parallelly spaced a predetermined distance apart to form a no go gage between them for magazine shell outside thickness, and the other pair of upstanding legs having upstanding facing surfaces parallelly spaced a greater predetermined distance apart to form a go gage for the shell outside thickness, a fiat surface on said cross member and at right angles to the upstanding surfaces of said other legs for indicating the squareness of said shell and the relative longitudinal position of said lips, one of said other pair of legs having a length from said fiat surface less than an acceptable distance from said lips to said st p and forming a go gage for the relative position of said stop and said lips and the other one of said other pair of legs having a length from said flat surface greater than the acceptable distance of said stop from said lips and forming a no go gage for said relative position of said stop, one of said other pair of legs having a stepped transverse thickness with the thinner portion having a thickness less than the acceptable distance between said lips and the thicker portion having a thickness greater than the acceptable distance between said lips forming a go and no go gage for the spacing of said lips.

References Cited UNITED STATES PATENTS 2,694,262 11/1954 Daniel 33-'201 LEONARD FORMAN, Primary Examiner ROGER A. FIELDS, Assistant Examiner 

